Radio system



Aug. 18, 1931. w. KUMMERER 1,819,469

RADIO SYSTEM Filed Feb. 1, 1926 INVENTOR WILHELM KUMMERER Patented Aug.18, 1931 STATES PATENT OFFICE -WILHELM KUMMERER, 0F BERLIN, GERMANY,ASSIG-NOR TO GESELLSCHAFT Fl'IlR DRAHTLOSE TELEGRAPHIE M. B. H., DIEBERLIN, GERMANY, A COR-PORATION OF GERMANY RADIO SYSTEM Applicationfiled February 1, 1926, Serial No. 85,083, and in Germany April 20,1925.

The present invention relates to means adapted to avoid changes in thenatural fre oscillation circuit, with the tuning circuit which iscoupled to the generator by a branch coupling, must be accomplished insuch a way that by the coupling there is caused an equal change in theohmic resistance of both the inductive as well as the capacitive branchof the tuning circuit. With this purpose in View, the circuit branch isconnected with a separate coil inserted in the tuning circuit, theuseful or load circuit being inductively coupled with said coil. Thenumber of the turns, and the position of the primary and of thesecondary coils are so chosen that the values of the resistancetransferred become equally large in the inductive as well as in thecapacitive branches of the tuning circuit. Of course, the coupling tothe tuning circuit need not necessarily be inductive in nature, indeed,it may be effected also by the aid of coupling condensers or byresistances. The invention is predicated upon that the united circuitsare tuned to the frequency of the tuning circuits, inasmuch as the endaimed at is attained only When by the coupling there is afi'ected solelya change in the ohmic resistance in the branches of the tuning circuits.

A clearer understanding will be had from a consideration of theaccompanying drawings in which I v Fig. 1 shows a .circuit diagramembodying this invention.

Fig. 2 shows a modified circuit.

In a circuit arrangement in accordance with the invention as illustratedin Fig. 1, R is an electron tube which is back-coupled to produceoscillations, L-C the working circuitwhich ordinarily contains only aself-inductance L and a capacity C. There is in serted in addition aninduction coil P, the supply lead being taken olf, at the middle of thesame, and this coil is so disposed that it will not be in coupledrelationship with coil L. A load circuit A (or an aerial) according tothe invention is so "coupled with coil P by means of the coil and themutual inductance of coils P and S is so set, that equal resistances aretransferred to both branches of the working circuit.

A further development of the invention consists in inserting in thecapacitive branch of the working circuit a further self-inductance coilin series with the condenser, the value or size of said coil being equalto the self-inductance of the inductive branch which is not used for thecoupling with the load gards their value, are nearly alike, but oppositein direction, with the result that overtones are precluded from the loadcircuit which must be coupled with the working circuit in a way ashereinbefore described An arrangement built in conformity with what hasbeen outlined is shown in Fig. 2.

The working circuit accordingty consists of the two equalself-inductance coils L and L and the coil P to'which in turn theworking circuit A is coupled b the aid of coil S in a way ashereinbeforj described.

The practical advantages ofi'ered by the in vent-ion in the case of atransmitter and a receiver, to the tuning circuit-of which the antennais connected, consist consequently in eliminating changes in thefrequencies of the tuning circuits in the presence of different degreesor factors of coupling. For transmitter arrangements with self-excitatim at. the frequency of the working circuit. it must be noted, thecoupling between this circuitand the antenna must, of course, beextremely loose in order that no wave decomposition may be produced. Therelations as stated of course presuppose the existance of impressedoscillations.

Having thus described my invention, what I claim is 1. In a radiofrequency system, a source of oscillations having a fundamental andharmonics existing therein, said source including a circuit tuned to thefundamental frequency having inductive and capacitive branches connectedin parallel and connected to said source of oscillations, said inductivebranch consisting of a coil and a portion of a coupling inductanceconnected in series, said capacitive branch consisting of a coil, acondenser and a second portion of a coupling inductance connected inseries and a load circuit coupled to eachof said coupling portionswhereby the introduction of harmonic frequencies in said load circuit issubstantially suppressed.

2. In combination an oscillation generator having an output circuitcomprising capacitive and inductive branches arranged in parallel, acoupling impedance, portions of which are connected in each of saidbranches, and a self inductance coil connected in and forming a part ofsaid capacitive-branch, an intermediate tuned oscillating circuitcoupled to said coupling impedance and means for coupling a utilizationcircuit to said intermediate circuit. I

3. In combination, an oscillation generator having an output circuitcomprising capacitive and inductive branches arranged in parallel and acoupling impedance portions of which are connected in each of saidbranches, an intermediate tuned oscillatory circuit coupled to saidcoupling impedance, a self inductance coil connected in said capacitivebranch the self inductance of which is approximately equal to the selfinductance of said inductive branch not utilized for coupling saidintermediate circuit and means for coupling a utilization circuit tosaid intermediate circuit.

WILH. KUMMERER.

